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CVE-2026-118261— Echo: Decompress permits unbounded gzip expansion in v4

Quick assessment

Affected
labstack echo
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Echo 是一个用 Go 语言编写的 Web 框架。在 4.0.0 至 4.16.1 版本中，Echo v4 的可选 Decompress 中间件在解压 gzip 编码的请求流时，未对其解压后的尺寸进行限制。这导致一个较小的压缩请求在处理器读取或绑定该请求时，可能膨胀为极大的请求体，从而消耗过多的内存或 CPU 资源；攻击者可通过发送重复或并发请求，引发拒绝服务（DoS）。该中间件默认未启用，且仅限制压缩请求的大小无法约束解压后的实际大小。此问题已在 4.16.1 版本中修复。

CVSS 8.2 · High

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 1

VendorProduct Version RangeStatus
labstack echo >= 4.0.0, < 4.16.1 affected
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I. Basic Information for CVE-2026-118261

Vulnerability Information
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Vulnerability Title
Echo: Decompress permits unbounded gzip expansion in v4
Source: CVE Program / CVE List V5
Vulnerability Description
Echo is a Go web framework. From 4.0.0 until 4.16.1, Echo v4's opt-in Decompress middleware exposes a gzip-decoded request stream without limiting its expanded size. A small compressed request can expand into a very large body when a handler reads or binds it, consuming excessive memory or CPU and allowing repeated or concurrent requests to cause denial of service. The middleware is not enabled by default, and limiting only the compressed request size does not bound the decoded size. This issue is fixed in 4.16.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
labstack echo >= 4.0.0, < 4.16.1 -

II. Public POCs for CVE-2026-118261

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III. Intelligence Information for CVE-2026-118261

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Other References for CVE-2026-118261 (3)

Same Patch Batch · labstack · 2026-10-28 · 16 CVEs total

CVE-2026-118264 9.1 CRITICAL Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls
CVE-2026-118260 8.2 HIGH Echo: BodyDump captures request and response bodies without size limits in v4
CVE-2026-118262 8.2 HIGH Echo: WebSocket proxy can retain connections and handlers after client disconnect
CVE-2026-118650 7.5 HIGH Echo: middleware.Static: `%2F`-encoded path bypasses route/group middleware guarding a sta
CVE-2026-118263 6.3 MEDIUM Echo: BodyDump can discard BodyLimit overflow errors for unknown-length requests
CVE-2026-118652 6.1 MEDIUM Echo: Reflected Cross-Site Scripting (XSS) via unsanitized JSONP callback in Context.JSONP
CVE-2026-118656 6.1 MEDIUM Echo: Open Redirect via Control-Character Prefix Defeating sanitizeURI
CVE-2026-118654 5.9 MEDIUM Echo static file middleware route protection bypass via encoded dot-dot traversal
CVE-2026-118655 5.9 MEDIUM Echo: Static Middleware Double-Unescape Path Traversal
CVE-2026-118657 5.9 MEDIUM Echo: HTTPS Redirect and HSTS Bypass via Unconditional Trust of Forwarded Scheme Headers
CVE-2026-118651 5.3 MEDIUM Echo: Reverse Proxy Forwards Attacker-Supplied X-Real-IP to Upstream by Default
CVE-2026-118266 5.3 MEDIUM Echo: CSRF Protection Bypass via MethodOverride Rewriting POST to Safe Method
CVE-2026-118265 5.3 MEDIUM Echo: X-Real-IP extractor trusts the header value instead of the sending peer
CVE-2026-118653 5.3 MEDIUM Echo: Rate Limiter Bypass via Spoofed X-Forwarded-For Header in Default Configuration
CVE-2026-118658 4.7 MEDIUM Echo: Arbitrary Scheme Injection in WWWRedirect/NonWWWRedirect Middlewares via X-Forwarded

IV. Related Vulnerabilities

Same product: echo
Same vendor: labstack
Same weakness: CWE-400